Although the detailed reaction mechanism has not yet been identified, discovery of this distinct function of a methane-producing PLP-dependent enzyme could presage a breakthrough in the practical application of methanotrophs. Diversifying genetic regulatory modules can allow delicate control of synthetic pathways that are activated on demand according to host plant physiology. Fascinating potential targets for dynamic regulation are small molecules involved in plant–microbe interactions and plant stress response. Ryu et al. recently constructed biosensors for natural and non-natural signaling molecules that enabled control of N fixation in various microbes. More recently, Herud-Sikimić et al. engineered an E. coli Trp repressor to a FRET-based auxin biosensor that undergoes conformational change in the presence of auxin-related molecules but not L-tryptophan Because the conformational change induced by L-tryptophan is a core function in the Trp operon, the engineered Trp repressor may allow auxin-dependent biosynthesis. Developing dynamic regulatory circuits for controlling expression of PGP traits may help maintain the viability of engineered host microbes in pre-existing microbiomes and thereby facilitate their potential contributions to sustainable agriculture. In nature, plants interact with multiple PGPRs whose properties may work cooperatively to provide benefits. For example, Kumar et al. observed synergistic effects of ACC deaminase- and siderophore-producing PGPRs that enhanced sunflower growth. This result implies that layering PGP traits in a host strain under single or multiple regulatory circuits may maximize their advantages. Furthermore, microbiome engineering inspired by native PGPR colonization, for example,through siderophore-utilizing ability,dutch bucket for sale may open a new era for sustainable agriculture via customized PGPR consortia. Agricultural science has been enormously successful in providing an inexpensive supply of high-quality and safe foods to developed and developing nations. These advancements have largely come from the implementation of technologies that focus on efficient production and distribution systems as well as selective breeding and genetic improvement of cultured plants and animals.

Although population growth in developed nations has reached a plateau, no slowdown is predicted in the developing world until about 2050, when the population of the world is expected to reach 9 billion . To meet the global food demand will require nearly double the current agricultural output, and 70% of that increased output must come from existing or new technologies . The global demand for animal products is also substantially growing, driven by a combination of population growth, urbanization, and rising incomes. However, at present, nearly 1 billion people are malnourished . Animal products contain concentrated sources of protein, which have AA compositions that complement those of cereal and other vegetable proteins, and contribute calcium, iron, zinc, and several B group vitamins. In developing countries where diets are based on cereals or bulky root crops, eggs, meat, and milk are critical for supplying energy in the form of fats. In addition, animal-derived foods contain compounds that actively promote long-term health, including bio-active compounds such as taurine, l-carnitine, creatine, and endogenous antioxidants such as carosine and anserine . Furthermore, those foods are a rich source of CLA, forms of which have anti-cancer properties , reduce the risk of cardiovascular disease , and help fight inflammation .Animal production will play a pivotal role in meeting the growing need for high-quality protein that will advance human health. Our technological prowess will be put to the test as we respond to a changing world and increasingly diverse stakeholders. Intensifying food production likely will be confounded by declining feed stock yields due to global climate change, natural resource depletion, and an increasing demand for limited water and land resources . Additionally, whereas the moral imperative to feed the malnourished people of the world is unequivocal, a well-fed, well-educated, and vocal citizenry in developed nations places a much greater emphasis on the environmental sustainability of production, the safety of food products, and animal welfare, often without regard for impact on the cost of the food. Despite these daunting challenges, the sheer magnitude of potential human suffering calls on us to assume the reins from our recently lost colleague, Norman Borlaug, to harness technological innovation within our disciplines to keep world poverty, hunger, and malnutrition at bay.

As was the case during the Green Revolution, advancements in genetics and breeding will provide a wellspring for a needed revolution in animal agriculture. Indeed, we have entered the era of the genome for most agricultural animal species. Genetic blueprints position us to refine our grasp of the relationships between genotype and phenotype and to understand the function of genes and their networks in regulating animal physiology. The tools are in hand for accelerating the improvement of agricultural animals to meet the demands of sustainability, increased productivity, and enhancement of animal welfare .The goals of animal genetic improvement are firmly grounded in the paradigm of animal production, which naturally refers to concepts of efficiency, productivity, and quality. Sustainability and animal welfare are central considerations in this paradigm; an inescapable principle is that the maximization of productivity cannot be accomplished without minimizing the levels of animal stress. Furthermore, the definition of efficiency requires sustainability. Unnecessary compromises to animal well-being or sustainability are morally reprehensible and economically detrimental to consumers and producers alike. The vast majority of outcomes from genetic selection have been beneficial for animal well-being. Geneticists try to balance the enrichment of desirable alleles with the need to maintain diversity because they are keenly aware of the vulnerability of monoculture to disease. Genetic improvement programs must always conserve genetic diversity for future challenges, both as archived germplasm and as live animals . However, unanticipated phenotypes occasionally arise from genetic selection for 2 reasons. First, every individual carries deleterious alleles that are masked in the heterozygous state but can be uncovered by selective breeding. Second, the linear organization of chromosomes leads to certain genes being closely linked to each other on the DNA molecules that are transmitted between generations. Thus, blind selection for an allele that is beneficial to 1 trait also enriches for all alleles that are closely linked to it and either through pleiotropy or linkage disequilibrium, undesirable correlated responses in other traits may occur.

Geneticists are aware of this and closely monitor the health and well-being of populations that are under selection to ensure that any decrease in fitness is detected and that ameliorative actions are taken to correct problems either by the elimination of carriers from production populations, altering the selection objective to facilitate improvement in the affected fitness traits, or by introducing beneficial alleles by crossbreeding. Increasingly precise molecular tools now allow the rapid identification of genetic variants that cause single-gene defects and facilitate the development of DNA diagnostics to serve in genetic management plans that advance the production of healthy animals. Whole-genome genotyping with high-density, SNP assays will enable the rapid determination of the overall utility of parental lines in a manner that is easily incorporated into traditional quantitative genetic improvement programs . The approach is known as genomic selection and essentially allows an estimation of the genetic merit of an individual by adding together the positive or negative contributions of alleles across the genome that are responsible for the genetic influence on the trait of interest. Under GS,hydroponic net pots genetic improvement can be accelerated by reducing the need for performance testing and by permitting an estimation of the genetic merit of animals outside currently used pedigrees. Genomic selection also provides for development of genetic diagnostics using experimental populations, which may then be translated to commercial populations, allowing, for the first time, the opportunity to select for traits such as disease resistance and feed efficiency in extensively managed species such as cattle. The presence of genotype × environment interactions will also require the development of experimental populations replicated across differing environmental conditions to enable global translation of GS. The speed with which the performance of animals can be improved by GS is determined by generation interval, litter, or family size, the frequency of desirable alleles in a population , and the proximity on chromosomes of good and bad alleles. Although predicting genetic merit using DNA diagnostics may be less precise than directly testing the performance of every animal or their offspring, the reduction in generation interval by far offsets this. For example, in dairy populations, the rate of genetic improvement is expected to double with the application of GS . Preliminary results from the poultry industry suggest that GS focused on leg health in broilers and livability in layers can rapidly and effectively improve animal welfare . Although price constraints currently limit the widespread adoption of high-density SNP genotyping assays in livestock species, low-cost, reduced-subset assays containing the most predictive 384 to 3,000 SNP are under development in sheep, beef, and dairy cattle.

These low-cost assays are expected to be rapidly adopted and will be expanded in content as the price of genotyping declines. Animal selection based on GS is also expected to reduce the loss of genetic diversity that occurs in traditional pedigree-based breeding because the ability to obtain estimates of genetic merit directly from genotypes avoids the restriction of selection to the currently used parental lineages. Also, despite the increase in the rate of genetic improvement, selection for complex traits involving hundreds or thousands of genes will not result in the rapid fixation of desirable alleles at all of the underlying loci.Whereas GS will accelerate animal improvement in the post genomic era, parallel and overlapping efforts in animal improvement based on genome-informed genetic engineering must ensue to ensure that productivity increases at pace with the expanding world populations. The tools of functional genomics and the availability of genome sequences provide detailed information that can be used to engineer precise changes in traits, as well as monitor any adverse effects of such changes on the animal . These tools are also enabling a deeper understanding of gene function and the integration of gene networks into our understanding animal physiology . This understanding has begun to identify major effect genes and critical nodes in genetic networks as potential targets for GE.The genomics revolution has been accompanied by a renaissance in GE technologies. Novel genes can be introduced into a genome , and existing genes can either be inactivated or their expression tuned to desirable levels using recently developed RNA interference . The specificity and efficiency of these approaches is expected to continue to improve. The technical advancements in GE are so significant that Greger advocated that scrutiny of the procedures for generating transgenic farm animals is undeserved and that discussion should focus on the welfare implications of the desired outcome instead of unintended consequences of GE. This position is also reflected by the rigorous regulatory mechanism established by the FDA for premarket approval of GE animals , which considers the risks of a given product to the environment and the potential impact on the well-being of animals and consumers. Indeed, this review mechanism was recently adopted as an international guideline by Codex Alimentarious , which has already found GE to be a safe and reliable approach to the genetic improvement of food animals . In addition, guidelines that promote good animal welfare, enhance credibility, and comply with current regulatory requirements, for the development and use of GE animals have been developed as a stewardship guidance . The stewardship guidance assists the industry and academia in developing and adopting stewardship principles for conducting research and developing and commercializing safe and efficacious agricultural and biomedical products from GE animals for societal benefit.Both GS and GE are viable, long-term approaches to genetic improvement, but when should one approach be employed over the other? Genes are not all equal in their effects upon changes in phenotype. The products encoded by some genes have major effects on biochemical pathways that define important characteristics or reactions in an organism. Other genes have lesser, but sometimes still important, effects. In general, genetic modification by GE is used to add major-effect genes, whereas genetic selection is applied to all genes, including the far larger number of lesser-effect genes that appear to be responsible for about 70% of the genetic variation within a given trait . One of the most significant advantages of GE is the ability to introduce new alleles that do not currently exist within a population, in particular, where the allele substitution effect would be very large. This approach can include gene supplementation and genome editing, the latter enabling the precise transfer of an alternative allele without any other changes to the genome of an animal .